Summary

A 35-year-old woman with a history of vitiligo, hypothyroidism and amenorrhoea presented with collapse and clinical features
of cardiac failure. Laboratory investigations revealed pancytopaenia, the cause of which was found to be vitamin B12 deficiency
due to pernicious anaemia. Treatment with intramuscular hydroxycobalamin was commenced and the patient improved steadily with
concomitant improvement in her haematological indices. Clinical features of pernicious anaemia which can include marked pancytopaenia,
diagnostic approach, associated conditions and approach to treatment are discussed. The importance of surveillance for gastrointestinal
malignancy is emphasised.